EP 3919637 B1 20231115 - HIGH-STRENGTH STEEL SHEET AND METHOD FOR PRODUCING SAME
Title (en)
HIGH-STRENGTH STEEL SHEET AND METHOD FOR PRODUCING SAME
Title (de)
HOCHFESTES STAHLBLECH UND VERFAHREN ZUR HERSTELLUNG DAVON
Title (fr)
TÔLE D'ACIER À HAUTE RÉSISTANCE ET PROCÉDÉ DE PRODUCTION D'UNE TELLE TÔLE D'ACIER
Publication
Application
Priority
- JP 2019012790 A 20190129
- JP 2019049749 W 20191219
Abstract (en)
[origin: EP3919637A1] Provided are a high-strength steel sheet having a low yield ratio and a method for producing the same. In the present invention, a high-strength steel sheet has a chemical composition containing, in mass%, C: 0.06% or greater and 0.120% or less, Si: 0.3% or greater and 0.7% or less, Mn: 1.6% or greater and 2.2% or less, P: 0.05% or less, S: 0.0050% or less, Al: 0.01% or greater and 0.20% or less, and N: 0.010% or less, with the balance being Fe and incidental impurities, and the high-strength steel sheet has a microstructure in which ferrite is present as a major phase, and martensite is present in an area fraction of 10% or greater and less than 50% relative to an area of an entirety of the microstructure, wherein the martensite has an average grain diameter of 3.0 µm or less; in an entirety of the martensite, a proportion of martensite having an aspect ratio of 3 or less is 60% or greater; and the martensite having an aspect ratio of 3 or less has a carbon concentration of 0.30% or greater and 0.90% or less in mass%.
IPC 8 full level
C21D 9/46 (2006.01); C21D 6/00 (2006.01); C21D 8/02 (2006.01); C21D 8/04 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); C23C 2/02 (2006.01); C23C 2/06 (2006.01); C23C 2/28 (2006.01); C23C 2/40 (2006.01); C22C 38/58 (2006.01)
CPC (source: EP KR US)
C21D 6/005 (2013.01 - EP); C21D 6/008 (2013.01 - EP); C21D 8/0226 (2013.01 - EP KR US); C21D 8/0236 (2013.01 - KR US); C21D 8/0263 (2013.01 - EP US); C21D 8/0273 (2013.01 - EP KR US); C21D 8/0284 (2013.01 - US); C21D 8/0426 (2013.01 - EP); C21D 8/0463 (2013.01 - EP); C21D 8/0473 (2013.01 - EP); C21D 9/46 (2013.01 - EP US); C22C 38/00 (2013.01 - EP); C22C 38/001 (2013.01 - KR US); C22C 38/002 (2013.01 - US); C22C 38/02 (2013.01 - EP KR US); C22C 38/04 (2013.01 - EP KR US); C22C 38/06 (2013.01 - EP KR US); C22C 38/22 (2013.01 - KR US); C22C 38/24 (2013.01 - KR US); C22C 38/26 (2013.01 - US); C22C 38/28 (2013.01 - US); C22C 38/32 (2013.01 - US); C22C 38/38 (2013.01 - KR); C22C 38/42 (2013.01 - US); C23C 2/02 (2013.01 - EP KR US); C23C 2/022 (2022.08 - EP KR US); C23C 2/06 (2013.01 - EP US); C23C 2/28 (2013.01 - EP KR US); C23C 2/29 (2022.08 - EP KR US); C23C 2/40 (2013.01 - EP US); C21D 2211/005 (2013.01 - EP US); C21D 2211/008 (2013.01 - EP KR US); C22C 38/58 (2013.01 - EP)
Designated contracting state (EPC)
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR
DOCDB simple family (publication)
EP 3919637 A1 20211208; EP 3919637 A4 20211208; EP 3919637 B1 20231115; CN 113366126 A 20210907; CN 113366126 B 20230922; JP 6809648 B1 20210106; JP WO2020158228 A1 20210218; KR 102508292 B1 20230309; KR 20210106556 A 20210830; MX 2021009099 A 20210908; US 2022098698 A1 20220331; WO 2020158228 A1 20200806
DOCDB simple family (application)
EP 19912317 A 20191219; CN 201980090854 A 20191219; JP 2019049749 W 20191219; JP 2020520081 A 20191219; KR 20217023532 A 20191219; MX 2021009099 A 20191219; US 201917426897 A 20191219